Leadership is widely recognized as an essential driver of organizational performance and improvement, but little is known about its role in driving quality of early childhood programs and outcomes for staff and families. In launching the Early Care and Education Leadership Study (ExCELS), the U.S. Department of Health and Human Services? Office of Planning, Research, and Evaluation (OPRE) seeks to fill the definitional and measurement gaps to help the early childhood field understand how effective leaders can improve quality experiences for families in early care and education (ECE) settings. OPRE contracted with Mathematica Policy Research and its subcontractor, the University of Massachusetts, Boston, to conduct this study. The study team will identify key leadership constructs, map out and test their associations to outcomes, and develop a short-form instrument to measure ECE leadership in center-based settings. Project staff and OPRE will partner with substantive, technical, and practical experts as well as a range of stakeholders from government agencies and leadership development programs to inform the work. This multi-phase study will:?Through a review of existing research literature, identify the key features of effective ECE leadership and highlight gaps in our understanding?Construct a theory of change that shows how ECE leaders can act as change agents for quality improvement?Develop a compendium of existing measures aligned with the theory of change to identify measurement gaps?Identify promising leadership quality improvement initiatives and methods of evaluating them?Conduct a descriptive study in 100 centers that receive funding from Head Start or the Child Care and Development Fund to test hypothesized associations between leadership constructs and outcomes in the theory of change